1. Field of the Invention
This invention relates in general to equipment for resecting bones during implant and prosthetic surgery so as to match a pattern.
2. Description of the Prior Art
During certain types of orthopedic surgery, there is a need to cut or resect away part of the bone to a desired shape. For example, in the case of grafting a donor bone section to replace a diseased bone section, portions of the donor bone joint must be shaped to resemble the diseased bone joint as much as possible. As another example, a tibial plateau prosthesis may be implanted in the leg of a user while retaining an existing femur. In that case, the existing femur must be resected to match the tibial plateau of the prosthesis as much as possible. In the prior art, this may be handled using high speed bone cutting or resecting equipment. A surgeon primarily relies on a visual comparison and skillful use of the equipment. The surgeon may also make molds to assist in performing the resection.
One means for resecting bone into a particular shape is disclosed by U.S. Pat. No. 5,190,547, issued on Mar. 2, 1993 to Forest C. Barber, Jr. and Durrell G. Tidwell, which is hereby incorporated by reference as if fully set forth herein. A replicator is disclosed for resecting bone to match a desired pattern. The replicator includes a frame with a pattern holder and a bone holder. A tool holder mounts to the frame by means of a four bar linkage assembly. A cutting tool and a probe are mounted to the tool holder. The four bar linkage allows three-dimensional movement of the tool holder, but constrains the tool holder to always be in parallel with a line extending through the pattern holder and a bone holder.
The pattern holder and tool holder of the replicator of the '547 patent are adjustable for repositioning a pattern and a bone for presentation to the probe and the cutting tool for different angles of approach. However, the pattern holder and the tool holder must be realigned to correctly align the pattern and the bone for presentation to the probe and cutting tool each time the positions are adjusted. Realignment primarily relies on visual comparison for determining proper alignment between the bone holder and pattern holder in a second position.